The impact of COVID-19 vaccination on glycaemic control in children and adolescents with type 1 diabetes mellitus on continuous glucose monitoring

Aims To investigate the impact of SARS-COV-2 vaccination on the glycaemic control in children and adolescents with T1DM wearing continuous glucose monitoring (CGM). Methods Caregivers of children and adolescents with T1DM were questioned regarding SARS-CoV-2 vaccination during their regular visits at the Pediatric Diabetes Outpatient Clinic. Data regarding Time in Range (TIR) (glucose levels: 70-180 mg/dl) 7 days prior and 7 days after a vaccination dose were collected in patients wearing CGM and data regarding insulin daily doses were also obtained for the insulin pump users. Results From a total of 135 patients eligible for SARS-CoV-2 vaccination, 70 (51.9%) children (37 boys, 52.9%) were vaccinated with at least one dose. Seven patients received only one dose, whereas two children received a third booster shot. No statistically significant difference was observed in either TIR (64.19% post vs. 65.53% pre, p = 0.158) or total daily insulin dose (40.08 U/day post vs. 39.32 U/day pre, p = 0,282). Additionally, in ten patients on Hybrid Closed-Loop System the percentage of the automated insulin boluses given post-vaccination was not statistically significant different compared to the boluses given pre-vaccination (15.80% vs. 16.90%, p = 0,491). Conclusions Vaccination against SARS-CoV-2 in children and adolescents with T1DM is safe and is not associated with immediate glucose imbalance.